A 39-year-old Mercedes man admitted to police he helped clean the gun that was used in a Oct. 16 murder, according to a criminal complaint obtained by CBS 4 News. (Photo courtesy of the Hidalgo County Sheriff's Office)

A 39-year-old Mercedes man admitted to investigators he helped clean the gun that was used in a Oct. 16 murder, according to a criminal complaint obtained by CBS 4 News.

New details from a criminal complaint say Villarreal met with 39-year-old Michael Chavez at a Stripes convenience store on the day of the murder of 38-year-old Gerardo Alberto Martinez.

Throughout the course of an investigation, investigators obtained surveillance video which showed Chavez arrive at his residence 20 minutes after the murder — with an unknown man — and dispose of the murder evidence, according to the criminal complaint.

On Monday, Dec. 4, investigators arrested Villarreal on unrelated charges, according to the criminal complaint.

According to the criminal complaint:

Jose admitted he is the person seen in the surveillance video with Michael Chavez and he cleans a gun, puts it in a bag and gives it to Michael. Jose stated that he saw Michael throw the gun into the trash can at Michael's house."

Investigators continue to search for Chavez. Anyone with information about Chavez's whereabouts is asked to call the Hidalgo County Sheriff's Office Criminal Investigations Division at 956-383-9114. Anonymous tips can be sent to the Hidalgo County Crime Stoppers hotline at 956-668-8477.